Carbon nanotubes (CNTs) are excellent scaffolds for advanced electrode materials, resulting from their intrinsic sp2 carbon hybridization, interconnected electron pathway, large aspect ratio, hierarchical porous str...Carbon nanotubes (CNTs) are excellent scaffolds for advanced electrode materials, resulting from their intrinsic sp2 carbon hybridization, interconnected electron pathway, large aspect ratio, hierarchical porous structures, and low cost at a large-scale production. How to make full utilization of the mass produced CNTs as building blocks for nanocomposite electrodes is not well understood yet. Herein, a composite cathode containing commercial agglomerated multi-walled CNTs and S for Li-S battery was fabricated by a facile melt-diffusion strategy. The hierarchical CNT@S coaxial nanocables exhibited a discharging capacity of 1020 and 740 mAh .g-1 at 0.5 and 2.0 C, respectively. A rapid capacity decay of 0.7% per cycle at the initial 10 cycles and a slow decay rate of 0.14% per cycle for the later 140 cycles were detected. Such hierarchical agglomerated CNT@ S cathodes show advantages in easy fabrication, environmentally benign, low cost, excellent scalability, and good Li ion storage performance, which are extraordinary composites for high performance Li-S battery.展开更多
Aqueous zinc-ion batteries(ZIBs)are receiving a continuously increasing attention for mobile devices,especially for the flexible and wearable electronics,due to their non-toxicity,non-flammability,and low-cost feature...Aqueous zinc-ion batteries(ZIBs)are receiving a continuously increasing attention for mobile devices,especially for the flexible and wearable electronics,due to their non-toxicity,non-flammability,and low-cost features.Despite the significant progress in achieving higher capacities for electrode materials of ZIBs,to endow them with high flexibility and economic feasibility is,however,still a significant challenge remaining unsolved.Herein,we present a highly flexible composite film composed of carbon nanotube film and V_(2)O_(5)(CNTF@V_(2)O_(5))with high strength and high conductivity,which is prepared by simply impregnating a porous CNT film with an aqueous V_(2)O_(5)sol under vacuum.For this material,intimate incorporation between V_(2)O_(5)and CNTs has been achieved,successfully integrating the high zinc ion storage capability with high mechanical flexibility.As a result,this CNTF@V_(2)O_(5)film delivers a high capacity of 356.6 m Ah g^(-1)at 0.4 A g^(-1)and excellent cycling stability with 80.1%capacity retention after 500 cycles at 2.0 A g^(-1).The novel strategy and the outstanding battery performance presented in this work should shed light on the development of high-performance and flexible ZIBs.展开更多
Experimental investigations on the vacuum outgassing of a carbon nanotube (CNT) cathode with high-intensity pulsed electron emission on a 2 MeV linear induction accelerator injector are presented. Under the 1.60 MV ...Experimental investigations on the vacuum outgassing of a carbon nanotube (CNT) cathode with high-intensity pulsed electron emission on a 2 MeV linear induction accelerator injector are presented. Under the 1.60 MV diode voltage, the CNT cathode could provide 1.67 kA electron beam with the amount of outgassing of about 0.51 Pa.L. It is found that the amount of outgassing, which determines the cathode emission current, depends on the diode voltage and the vacuum.展开更多
Realizing a lithium sulfide(Li_(2)S)cathode with both high energy density and a long lifespan requires an innovative cathode design that maximizes electrochemical performance and resists electrode deterioration.Herein...Realizing a lithium sulfide(Li_(2)S)cathode with both high energy density and a long lifespan requires an innovative cathode design that maximizes electrochemical performance and resists electrode deterioration.Herein,a high-loading Li_(2)S-based cathode with micrometric Li_(2)S particles composed of two-dimensional graphene(Gr)and one-dimensional carbon nanotubes(CNTs)in a compact geometry is developed,and the role of CNTs in stable cycling of high-capacity Li–S batteries is emphasized.In a dimensionally combined carbon matrix,CNTs embedded within the Gr sheets create robust and sustainable electron diffusion pathways while suppressing the passivation of the active carbon surface.As a unique point,during the first charging process,the proposed cathode is fully activated through the direct conversion of Li_(2)S into S_(8) without inducing lithium polysulfide formation.The direct conversion of Li_(2)S into S_(8) in the composite cathode is ubiquitously investigated using the combined study of in situ Raman spectroscopy,in situ optical microscopy,and cryogenic transmission electron microscopy.The composite cathode demonstrates unprecedented electrochemical properties even with a high Li_(2)S loading of 10 mg cm^(–2);in particular,the practical and safe Li–S full cell coupled with a graphite anode shows ultra-long-term cycling stability over 800 cycles.展开更多
Vanadium pentoxide (V205) exhibits high theoretical capacities when used as a cathode in lithium ion batteries (LIBs), but its application is limited by its structural instability as well as its low lithium and el...Vanadium pentoxide (V205) exhibits high theoretical capacities when used as a cathode in lithium ion batteries (LIBs), but its application is limited by its structural instability as well as its low lithium and electronic conductivities. A porous composite of V2Os-SnO2/carbon nanotubes (CNTs) was prepared by a hydrothermal method and followed by thermal treatment. The small particles of V205, their porous structure and the coexistence of SnO2 and CNTs can all facilitate the diffusion rates of the electrons and lithium ions. Electrochemical impedance spectra indicated higher ionic and electric conductivities, as compared to commercial V205. The VzOs-SnOz/CNTs composite gave a reversible discharge capacity of 198 mAh.g- 1 at the voltage range of 2.05-4.0 V, measured at a current rate of 200 mA.g-1, while that of the commercial V205 was only 88 mAh.g-1, demonstrating that the porous V2Os-SnOz/CNTs composite is a promising candidate for high-performance lithium secondary batteries.展开更多
In order to develop miniaturized and integrated electron vacuum devices, the electron beam modulation in a field- emission (FE) electron gun based on carbon nanotubes is researched. By feeding a high-frequency field...In order to develop miniaturized and integrated electron vacuum devices, the electron beam modulation in a field- emission (FE) electron gun based on carbon nanotubes is researched. By feeding a high-frequency field between the cathode and the anode, the steady FE electron beam can be modulated in the electron gun. The optimal structure of the electron gun is discovered using 3D electromagnetism simulation software, and the FE electron gun is simulated by PIC simulation software. The results show that a broadband (74-114 GHz) modulation can be achieved by the electron gun with a rhombus channel, and the modulation amplitude of the beam current increases with the increases in the input power and the electrostatic field.展开更多
In the given work the adsorption properties of molecule curcumin((1 E,6 E)-1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione) on CNT(8,0-6) nanotube were investigated by the density functional theory(DFT) in...In the given work the adsorption properties of molecule curcumin((1 E,6 E)-1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione) on CNT(8,0-6) nanotube were investigated by the density functional theory(DFT) in the solvent water for the first time. The non-bonded interaction effects of compounds curcumin and CNT(8,0-6) nanotube on the electronic properties, UV/Vis spectra, chemical shift tensors and natural charges were determined and discussed. The electronic spectra of the compound curcumin and the complex CNT(8,0-6)/curcumin in the solvent water were calculated by time dependent density functional theory(TD-DFT) for investigation of the maximum wavelength value of molecule Curcumin before and after the non-bonded interaction with the CNT(8,0-6) nanotube and molecular orbitals involved in the formation of absorption spectrum of the complex CNT(8,0-6)/curcumin at maximum wavelength.展开更多
Mixed ionic-electronic conductors in the family of LaxSr1-xCoyFe1-y O3-δ have been widely studied as cathode materials for solid oxide fuel cells (SOFCs). However, the long-term stability was a concern. Here we rep...Mixed ionic-electronic conductors in the family of LaxSr1-xCoyFe1-y O3-δ have been widely studied as cathode materials for solid oxide fuel cells (SOFCs). However, the long-term stability was a concern. Here we report our findings on the effect of a thin film coating of La0.85Sr0.15MnO3-δ (LSM) on the performance of a porous La0.6Sr0.4Co0.2Feo.8O3-δ(LSCF) cathode. When the thicknesses of the LSM coatings are appropriate, an LSM-coated LSCF electrode showed better stability and lower polarization (or higher activity) than the blank LSCF cathode without LSM infiltration. An anode-supported cell with an LSM-infiltrated LSCF cathode demonstrated at 825 ℃ a peak power density of -1.07 W/cm2, about 24% higher than that of the same cell without LSM infiltration (-0.86 W/cm2). Further, the LSM coating enhanced the stability of the electrode; there was little degradation in performance for the cell with an LSM-infiltrated LSCF cathode during 100 h operation.展开更多
A fringelike field emission with high-luminescence and stable emission current from screen-printed carbon nanotube mixed zinc oxide (CNT-ZnO) composite cathode was investigated. The luminescent patterns are significan...A fringelike field emission with high-luminescence and stable emission current from screen-printed carbon nanotube mixed zinc oxide (CNT-ZnO) composite cathode was investigated. The luminescent patterns are significantly different from those observed in the field emission measure of pure CNT cathode. SEM images reveal that the CNTs are perfectly matched with ZnO powders by filling the interspaces in CNT film. XRD analysis demonstrates that the CNTs and ZnO have a high degree of crystalline perfection. Field emission measurement exhibits that the turn-on field of CNT-ZnO cathode is 2.08 V/μm, lower than 2.46 V/μm for pure CNT cathode. The large fringelike emission current at the brims of CNT-ZnO cathode is attributed to a combination of the increased effective contact area of CNTs, which decrease the sheet resistance of cathode film, and the dangled CNT bundles at the brims of CNT-ZnO film cathode.展开更多
The cathode material La1-xSrxCuO3-δ(x=0.15, 0.2, 0.3, 0.4) was synthesized by a sol-gel method. X-ray diffraction reveals that a single phase of perovskite is formed. The investigation of the electrical properties su...The cathode material La1-xSrxCuO3-δ(x=0.15, 0.2, 0.3, 0.4) was synthesized by a sol-gel method. X-ray diffraction reveals that a single phase of perovskite is formed. The investigation of the electrical properties suggests that La0.7Sr0.3CuO3-δ has the highest electrical conductivity. La0.7Sr0.3CuO3-δ powder was mixed with different amount SDC (Sm0.15Ce0.85O1.925) powder (5wt.%-30wt.%) as composite cathodes. Electrochemical properties of the composite cathodes were researched further. Investigation suggests that the addition of appropriate amount SDC to La0.7Sr0.3CuO3-δ can improve the electrochemical properties and obtain better cathodic performance. Using La0.7Sr0.3CuO3-δ-SDC composite materials as a cathode based on SDC electrolyte, higher current density and power density at intermediate temperatures can be obtained.展开更多
La0.8Sr0.2FeO3-δ is a new kind of cathode material for intermediate SOFC, but its electrochemical activity is relative poor for the lanthanum gallate based solid oxide fuel cell. In this paper, a novel composite cath...La0.8Sr0.2FeO3-δ is a new kind of cathode material for intermediate SOFC, but its electrochemical activity is relative poor for the lanthanum gallate based solid oxide fuel cell. In this paper, a novel composite cathode of La0.8Sr0.2FeO3-δ/La0.9Sr0.1Ga0.8Mg0.2O3-δ was prepared on the LSGM electrolyte substrate by screen-printing method. The results of cathodic polarization measurements show that the overpotential decreases significantly when the composite cathode is used instead of the La0.8Sr0.2FeO3-δ single layer cathode. The cathodic overpotential of the composite La0.8Sr0.2FeO3-δ/La0.9Sr0.1Ga0.8Mg0.2O3-δ cathode is 150 mV at the current density of 0.2 A·cm-2 at 800 ℃, while the cathodic overpotential of the La0.8Sr0.2FeO3-δ single layer cathode is higher than 260 mV at the same condition. The electrochemical impedance spectroscopy was employed to investigate the polarization resistance of the cathode. The polarization resistance of the composite cathode is 1.20 Ω·cm2 in open circuit condition, while the value of the single La0.8Sr0.2FeO3-δ cathode is 1.235 Ω·cm2.展开更多
In the present work, the interaction between drug Granisetron(GRS) and BN(7,7-7) nanotube by density functional theory(DFT) calculations in the solvent water has been investigated. The non-bonded interaction effects o...In the present work, the interaction between drug Granisetron(GRS) and BN(7,7-7) nanotube by density functional theory(DFT) calculations in the solvent water has been investigated. The non-bonded interaction effects of the molecule GRS with BN(7,7-7) nanotube on chemical shift tensors, natural charge and electronic properties such as the energy gap between HOMO and LUMO, global hardness, electronegativity and electronic chemical potential have been also detected. The natural bond orbital(NBO) analysis suggested that charge transfer depended between GRS and nanotube and induces a dipole moment in the complex. Then, the possibility of the use of BN(7,7-7) nanotube for GRS delivery to the diseased cells has been established.展开更多
A new lithium ion battery cathode material, composite oxide LiNi y Co z Mn 1- y-z O 2, was synthesized. The structure and physical properties of the material, including composition, distribution of size, density and s...A new lithium ion battery cathode material, composite oxide LiNi y Co z Mn 1- y-z O 2, was synthesized. The structure and physical properties of the material, including composition, distribution of size, density and specific surface area, were discussed. The characteristic of charge and discharge, reversible specific capacity and cycle property were also studied. The relationship between the structure and properties of the composite oxides was explored. The results show that the composite oxide with a reasonable composition is beneficial to the improvement and enhancement of the properties.展开更多
The spinel LiMn_2O_(4-δ)Fδ cathode materials were synthesized by solid-state reaction, With calculated amounts of LiOH·H_2O, MnO_2(EMD). LiF. The results of electrochemical test demonstrated that these new mate...The spinel LiMn_2O_(4-δ)Fδ cathode materials were synthesized by solid-state reaction, With calculated amounts of LiOH·H_2O, MnO_2(EMD). LiF. The results of electrochemical test demonstrated that these new materials exhibited excellent electrochemical properties.Its initial capacity reached -115 mAb·g^(-1) and reversible efficiency is about 100%. After 60 cycles. its capacity was still around 110 mAh· g^(-1), with nearly 100% reversible efficiency,展开更多
To improve the cyclic stability at high temperature and thermal stability, the spherical Al2O3-modified Li(Ni0.5Co0.2Mn0.3)O2 was synthesized by a modified co-precipitation method, and the physical and electrochemic...To improve the cyclic stability at high temperature and thermal stability, the spherical Al2O3-modified Li(Ni0.5Co0.2Mn0.3)O2 was synthesized by a modified co-precipitation method, and the physical and electrochemical properties were studied. The TEM images showed that Li(Ni0.5Co0.2Mn0.3)O2 was modified successfully with nano-Al2O3. The discharge capacity retention of Al2O3-modified Li(Ni0.5Co0.2Mn0.3)O2 maintained about 99% after 200 cycles at high temperature(55 ℃), while that of the bare one was only 86%. Also, unlike bare Li(Ni0.5Co0.2Mn0.3)O2, the Al2O3-modified material cathode exhibited good thermal stability.展开更多
The cathode material Pr0.7Sr0.3Co1-yCuyO3-δ (y=0.05~0.3) was synthesized by a sol-gel method. X-ray diffraction indicated that the samples with y≤0.2 were single phase orthorhombic perovskite structure, but in the ...The cathode material Pr0.7Sr0.3Co1-yCuyO3-δ (y=0.05~0.3) was synthesized by a sol-gel method. X-ray diffraction indicated that the samples with y≤0.2 were single phase orthorhombic perovskite structure, but in the case of y=0.3, traces of a second phase were observed. The unit cell volumes increased with increasing copper content. The electrical conductivity decreased gradually with increasing Cu addition. The investigation of the electrochemical performance suggested that the sample with y=0.1 exhibited the lowest overpotential in all prepared Pr0.7Sr0.3Co1-yCuyO3-δ. With Pr0.7Sr0.3Co0.9Cu0.1O3-δ cathode and porous NiO/Ce0.8Sm0.2O1.9 anode, the single cell based on SDC thin film electrolyte was obtained by a simple dry pressing process. Maximum power densities of the cell were 406 and 481 mW·cm-2 at 700 and 750 ℃, respectively.展开更多
A series samples of La0.6M0.4FeO3-δ (M = Ca, Sr, process (GNP). FTIR, TG-DSC, XRD and TEM techniques Ba) perovskite-type oxides were prepared by glycine nitrate were used to characterize the chemical constitution...A series samples of La0.6M0.4FeO3-δ (M = Ca, Sr, process (GNP). FTIR, TG-DSC, XRD and TEM techniques Ba) perovskite-type oxides were prepared by glycine nitrate were used to characterize the chemical constitution, thermal stability and phase structure. The electrical conductivity of the samples was investigated by four-probe technique. With the increase of substituted-ionic radius, the temperature of phase formation increases, and the solid solubility decreases gradually, respectively. The La0.6Ca0.4FeO3-δ(LCF)powder is pure cubic perovskite-type crystalline after fired at 850℃ for 2 h. The XRD patterns of La0.6Sr0.4FeO3-δ(LSF) powder shows a small quantity of SrO peaks sintered at 1050℃ for 2 h. The electrical conductivity of LCF and LSF at 500 - 800℃ is over 100 S·cm^ - 1, and the value of LCF is 1170 S·cm^ - 1 at 800℃, which indicate that LCF and LSF may be used as a profitable cathode for IT-SOFCs. The characteristic of La0.6 Ba0.4FeO3-δ(LBF) is poor, and the electrical conductivity at intermediate temperatures is 1/20 less than that of LSF.展开更多
La0.8Sr0.2Co1-yFeyO3-δ (y=0.2, 0.4, 0.6, 0.8) powders were synthesized by ethylenediamine tetraacetic acid (EDTA) complexing sol-gel process. The powders were characterized via X-ray diffraction (XRD) and scanning el...La0.8Sr0.2Co1-yFeyO3-δ (y=0.2, 0.4, 0.6, 0.8) powders were synthesized by ethylenediamine tetraacetic acid (EDTA) complexing sol-gel process. The powders were characterized via X-ray diffraction (XRD) and scanning electron microscope and energy dispersive X-ray spectroscopy (SEM-EDS). The results showed that single-phased perovskite-type oxide powders with small particle size were obtained by the process, and the compositions of the productions agreed with the designed molar ratio. The electronic conductivity and ionic conductivity of La0.8Sr0.2Co1-yFeyO3-δ were investigated by DC four-terminal method and AC impedance spectroscopy, respectively. The electronic conductivity of La0.8Sr0.2Co1-yFeyO3-δ is approximately 2~4 orders of magnitude higher than the ionic conductivity. It was confirmed that the conductivities of the materials were strongly influenced by the composition anions, temperature and sample preparing process.展开更多
基金supported by National Basic Research Program of China (973 Program, 2011CB932602)Research Fund for the Doctoral Program of Higher Education of China (20120002120047)China Postdoctoral Science Foundation (2012M520293)
文摘Carbon nanotubes (CNTs) are excellent scaffolds for advanced electrode materials, resulting from their intrinsic sp2 carbon hybridization, interconnected electron pathway, large aspect ratio, hierarchical porous structures, and low cost at a large-scale production. How to make full utilization of the mass produced CNTs as building blocks for nanocomposite electrodes is not well understood yet. Herein, a composite cathode containing commercial agglomerated multi-walled CNTs and S for Li-S battery was fabricated by a facile melt-diffusion strategy. The hierarchical CNT@S coaxial nanocables exhibited a discharging capacity of 1020 and 740 mAh .g-1 at 0.5 and 2.0 C, respectively. A rapid capacity decay of 0.7% per cycle at the initial 10 cycles and a slow decay rate of 0.14% per cycle for the later 140 cycles were detected. Such hierarchical agglomerated CNT@ S cathodes show advantages in easy fabrication, environmentally benign, low cost, excellent scalability, and good Li ion storage performance, which are extraordinary composites for high performance Li-S battery.
基金supported by the National Natural Science Foundation of China(No.51072130,51502045 and 21905202)the Australian Research Council(ARC)through Discovery Project(No.DP200100365)the Discovery Early Career Researcher Award(DECRA,No.DE170100871)program。
文摘Aqueous zinc-ion batteries(ZIBs)are receiving a continuously increasing attention for mobile devices,especially for the flexible and wearable electronics,due to their non-toxicity,non-flammability,and low-cost features.Despite the significant progress in achieving higher capacities for electrode materials of ZIBs,to endow them with high flexibility and economic feasibility is,however,still a significant challenge remaining unsolved.Herein,we present a highly flexible composite film composed of carbon nanotube film and V_(2)O_(5)(CNTF@V_(2)O_(5))with high strength and high conductivity,which is prepared by simply impregnating a porous CNT film with an aqueous V_(2)O_(5)sol under vacuum.For this material,intimate incorporation between V_(2)O_(5)and CNTs has been achieved,successfully integrating the high zinc ion storage capability with high mechanical flexibility.As a result,this CNTF@V_(2)O_(5)film delivers a high capacity of 356.6 m Ah g^(-1)at 0.4 A g^(-1)and excellent cycling stability with 80.1%capacity retention after 500 cycles at 2.0 A g^(-1).The novel strategy and the outstanding battery performance presented in this work should shed light on the development of high-performance and flexible ZIBs.
文摘Experimental investigations on the vacuum outgassing of a carbon nanotube (CNT) cathode with high-intensity pulsed electron emission on a 2 MeV linear induction accelerator injector are presented. Under the 1.60 MV diode voltage, the CNT cathode could provide 1.67 kA electron beam with the amount of outgassing of about 0.51 Pa.L. It is found that the amount of outgassing, which determines the cathode emission current, depends on the diode voltage and the vacuum.
基金Korea Institute of Energy Technology Evaluation and Planning,Grant/Award Number:20214000000320Samsung Research Funding&Incubation Center of Samsung Electronics,Grant/Award Number:SRFC-MA1901-06。
文摘Realizing a lithium sulfide(Li_(2)S)cathode with both high energy density and a long lifespan requires an innovative cathode design that maximizes electrochemical performance and resists electrode deterioration.Herein,a high-loading Li_(2)S-based cathode with micrometric Li_(2)S particles composed of two-dimensional graphene(Gr)and one-dimensional carbon nanotubes(CNTs)in a compact geometry is developed,and the role of CNTs in stable cycling of high-capacity Li–S batteries is emphasized.In a dimensionally combined carbon matrix,CNTs embedded within the Gr sheets create robust and sustainable electron diffusion pathways while suppressing the passivation of the active carbon surface.As a unique point,during the first charging process,the proposed cathode is fully activated through the direct conversion of Li_(2)S into S_(8) without inducing lithium polysulfide formation.The direct conversion of Li_(2)S into S_(8) in the composite cathode is ubiquitously investigated using the combined study of in situ Raman spectroscopy,in situ optical microscopy,and cryogenic transmission electron microscopy.The composite cathode demonstrates unprecedented electrochemical properties even with a high Li_(2)S loading of 10 mg cm^(–2);in particular,the practical and safe Li–S full cell coupled with a graphite anode shows ultra-long-term cycling stability over 800 cycles.
基金supported by the National Natural Science Foundation of China (No. 51001098)the Institute of Metal Research of CAS (No. 09NBA211A1)
文摘Vanadium pentoxide (V205) exhibits high theoretical capacities when used as a cathode in lithium ion batteries (LIBs), but its application is limited by its structural instability as well as its low lithium and electronic conductivities. A porous composite of V2Os-SnO2/carbon nanotubes (CNTs) was prepared by a hydrothermal method and followed by thermal treatment. The small particles of V205, their porous structure and the coexistence of SnO2 and CNTs can all facilitate the diffusion rates of the electrons and lithium ions. Electrochemical impedance spectra indicated higher ionic and electric conductivities, as compared to commercial V205. The VzOs-SnOz/CNTs composite gave a reversible discharge capacity of 198 mAh.g- 1 at the voltage range of 2.05-4.0 V, measured at a current rate of 200 mA.g-1, while that of the commercial V205 was only 88 mAh.g-1, demonstrating that the porous V2Os-SnOz/CNTs composite is a promising candidate for high-performance lithium secondary batteries.
基金Project supported by the National Basic Research Program of China(Grant No.2013CB933603)the National Natural Science Foundation of China(Grant Nos.U1134006 and 61101041)
文摘In order to develop miniaturized and integrated electron vacuum devices, the electron beam modulation in a field- emission (FE) electron gun based on carbon nanotubes is researched. By feeding a high-frequency field between the cathode and the anode, the steady FE electron beam can be modulated in the electron gun. The optimal structure of the electron gun is discovered using 3D electromagnetism simulation software, and the FE electron gun is simulated by PIC simulation software. The results show that a broadband (74-114 GHz) modulation can be achieved by the electron gun with a rhombus channel, and the modulation amplitude of the beam current increases with the increases in the input power and the electrostatic field.
基金supported by the National Academy of Sciences of Belarus
文摘In the given work the adsorption properties of molecule curcumin((1 E,6 E)-1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione) on CNT(8,0-6) nanotube were investigated by the density functional theory(DFT) in the solvent water for the first time. The non-bonded interaction effects of compounds curcumin and CNT(8,0-6) nanotube on the electronic properties, UV/Vis spectra, chemical shift tensors and natural charges were determined and discussed. The electronic spectra of the compound curcumin and the complex CNT(8,0-6)/curcumin in the solvent water were calculated by time dependent density functional theory(TD-DFT) for investigation of the maximum wavelength value of molecule Curcumin before and after the non-bonded interaction with the CNT(8,0-6) nanotube and molecular orbitals involved in the formation of absorption spectrum of the complex CNT(8,0-6)/curcumin at maximum wavelength.
基金supported by the Department of Energy (National Energy Technology Laboratory) SECA Core Technology Program under Award Number DE-NT0006557 and DE-FE0009652by NSFC under grant No.51002182
文摘Mixed ionic-electronic conductors in the family of LaxSr1-xCoyFe1-y O3-δ have been widely studied as cathode materials for solid oxide fuel cells (SOFCs). However, the long-term stability was a concern. Here we report our findings on the effect of a thin film coating of La0.85Sr0.15MnO3-δ (LSM) on the performance of a porous La0.6Sr0.4Co0.2Feo.8O3-δ(LSCF) cathode. When the thicknesses of the LSM coatings are appropriate, an LSM-coated LSCF electrode showed better stability and lower polarization (or higher activity) than the blank LSCF cathode without LSM infiltration. An anode-supported cell with an LSM-infiltrated LSCF cathode demonstrated at 825 ℃ a peak power density of -1.07 W/cm2, about 24% higher than that of the same cell without LSM infiltration (-0.86 W/cm2). Further, the LSM coating enhanced the stability of the electrode; there was little degradation in performance for the cell with an LSM-infiltrated LSCF cathode during 100 h operation.
文摘A fringelike field emission with high-luminescence and stable emission current from screen-printed carbon nanotube mixed zinc oxide (CNT-ZnO) composite cathode was investigated. The luminescent patterns are significantly different from those observed in the field emission measure of pure CNT cathode. SEM images reveal that the CNTs are perfectly matched with ZnO powders by filling the interspaces in CNT film. XRD analysis demonstrates that the CNTs and ZnO have a high degree of crystalline perfection. Field emission measurement exhibits that the turn-on field of CNT-ZnO cathode is 2.08 V/μm, lower than 2.46 V/μm for pure CNT cathode. The large fringelike emission current at the brims of CNT-ZnO cathode is attributed to a combination of the increased effective contact area of CNTs, which decrease the sheet resistance of cathode film, and the dangled CNT bundles at the brims of CNT-ZnO film cathode.
文摘The cathode material La1-xSrxCuO3-δ(x=0.15, 0.2, 0.3, 0.4) was synthesized by a sol-gel method. X-ray diffraction reveals that a single phase of perovskite is formed. The investigation of the electrical properties suggests that La0.7Sr0.3CuO3-δ has the highest electrical conductivity. La0.7Sr0.3CuO3-δ powder was mixed with different amount SDC (Sm0.15Ce0.85O1.925) powder (5wt.%-30wt.%) as composite cathodes. Electrochemical properties of the composite cathodes were researched further. Investigation suggests that the addition of appropriate amount SDC to La0.7Sr0.3CuO3-δ can improve the electrochemical properties and obtain better cathodic performance. Using La0.7Sr0.3CuO3-δ-SDC composite materials as a cathode based on SDC electrolyte, higher current density and power density at intermediate temperatures can be obtained.
基金This work was financially supported by the National Natural Science Foundation of China (No. 90510006) and the National High-Tech Research and Development of China (No. 2003AA302440).
文摘La0.8Sr0.2FeO3-δ is a new kind of cathode material for intermediate SOFC, but its electrochemical activity is relative poor for the lanthanum gallate based solid oxide fuel cell. In this paper, a novel composite cathode of La0.8Sr0.2FeO3-δ/La0.9Sr0.1Ga0.8Mg0.2O3-δ was prepared on the LSGM electrolyte substrate by screen-printing method. The results of cathodic polarization measurements show that the overpotential decreases significantly when the composite cathode is used instead of the La0.8Sr0.2FeO3-δ single layer cathode. The cathodic overpotential of the composite La0.8Sr0.2FeO3-δ/La0.9Sr0.1Ga0.8Mg0.2O3-δ cathode is 150 mV at the current density of 0.2 A·cm-2 at 800 ℃, while the cathodic overpotential of the La0.8Sr0.2FeO3-δ single layer cathode is higher than 260 mV at the same condition. The electrochemical impedance spectroscopy was employed to investigate the polarization resistance of the cathode. The polarization resistance of the composite cathode is 1.20 Ω·cm2 in open circuit condition, while the value of the single La0.8Sr0.2FeO3-δ cathode is 1.235 Ω·cm2.
基金supported by the Islamic Azad University of Genaveh
文摘In the present work, the interaction between drug Granisetron(GRS) and BN(7,7-7) nanotube by density functional theory(DFT) calculations in the solvent water has been investigated. The non-bonded interaction effects of the molecule GRS with BN(7,7-7) nanotube on chemical shift tensors, natural charge and electronic properties such as the energy gap between HOMO and LUMO, global hardness, electronegativity and electronic chemical potential have been also detected. The natural bond orbital(NBO) analysis suggested that charge transfer depended between GRS and nanotube and induces a dipole moment in the complex. Then, the possibility of the use of BN(7,7-7) nanotube for GRS delivery to the diseased cells has been established.
文摘A new lithium ion battery cathode material, composite oxide LiNi y Co z Mn 1- y-z O 2, was synthesized. The structure and physical properties of the material, including composition, distribution of size, density and specific surface area, were discussed. The characteristic of charge and discharge, reversible specific capacity and cycle property were also studied. The relationship between the structure and properties of the composite oxides was explored. The results show that the composite oxide with a reasonable composition is beneficial to the improvement and enhancement of the properties.
文摘The spinel LiMn_2O_(4-δ)Fδ cathode materials were synthesized by solid-state reaction, With calculated amounts of LiOH·H_2O, MnO_2(EMD). LiF. The results of electrochemical test demonstrated that these new materials exhibited excellent electrochemical properties.Its initial capacity reached -115 mAb·g^(-1) and reversible efficiency is about 100%. After 60 cycles. its capacity was still around 110 mAh· g^(-1), with nearly 100% reversible efficiency,
基金Funded by the National High Technology Research and Development Program of China(863 Program)(No.2015AA034600)Province Science and Technology in Anhui(No.1301021011)
文摘To improve the cyclic stability at high temperature and thermal stability, the spherical Al2O3-modified Li(Ni0.5Co0.2Mn0.3)O2 was synthesized by a modified co-precipitation method, and the physical and electrochemical properties were studied. The TEM images showed that Li(Ni0.5Co0.2Mn0.3)O2 was modified successfully with nano-Al2O3. The discharge capacity retention of Al2O3-modified Li(Ni0.5Co0.2Mn0.3)O2 maintained about 99% after 200 cycles at high temperature(55 ℃), while that of the bare one was only 86%. Also, unlike bare Li(Ni0.5Co0.2Mn0.3)O2, the Al2O3-modified material cathode exhibited good thermal stability.
基金the National Natural Science Foundation of China (10674034)
文摘The cathode material Pr0.7Sr0.3Co1-yCuyO3-δ (y=0.05~0.3) was synthesized by a sol-gel method. X-ray diffraction indicated that the samples with y≤0.2 were single phase orthorhombic perovskite structure, but in the case of y=0.3, traces of a second phase were observed. The unit cell volumes increased with increasing copper content. The electrical conductivity decreased gradually with increasing Cu addition. The investigation of the electrochemical performance suggested that the sample with y=0.1 exhibited the lowest overpotential in all prepared Pr0.7Sr0.3Co1-yCuyO3-δ. With Pr0.7Sr0.3Co0.9Cu0.1O3-δ cathode and porous NiO/Ce0.8Sm0.2O1.9 anode, the single cell based on SDC thin film electrolyte was obtained by a simple dry pressing process. Maximum power densities of the cell were 406 and 481 mW·cm-2 at 700 and 750 ℃, respectively.
基金Project Supported bythe Natural Science Foundation of Bureau Education Anhui Province (N2004kj326)
文摘A series samples of La0.6M0.4FeO3-δ (M = Ca, Sr, process (GNP). FTIR, TG-DSC, XRD and TEM techniques Ba) perovskite-type oxides were prepared by glycine nitrate were used to characterize the chemical constitution, thermal stability and phase structure. The electrical conductivity of the samples was investigated by four-probe technique. With the increase of substituted-ionic radius, the temperature of phase formation increases, and the solid solubility decreases gradually, respectively. The La0.6Ca0.4FeO3-δ(LCF)powder is pure cubic perovskite-type crystalline after fired at 850℃ for 2 h. The XRD patterns of La0.6Sr0.4FeO3-δ(LSF) powder shows a small quantity of SrO peaks sintered at 1050℃ for 2 h. The electrical conductivity of LCF and LSF at 500 - 800℃ is over 100 S·cm^ - 1, and the value of LCF is 1170 S·cm^ - 1 at 800℃, which indicate that LCF and LSF may be used as a profitable cathode for IT-SOFCs. The characteristic of La0.6 Ba0.4FeO3-δ(LBF) is poor, and the electrical conductivity at intermediate temperatures is 1/20 less than that of LSF.
基金the National Natural Science Foundation of China (50204007)the Talent Foundation of Yunnan Province (2005PY01-33)Programfor New Century Excellent Talents in University (NCET-07-0387)
文摘La0.8Sr0.2Co1-yFeyO3-δ (y=0.2, 0.4, 0.6, 0.8) powders were synthesized by ethylenediamine tetraacetic acid (EDTA) complexing sol-gel process. The powders were characterized via X-ray diffraction (XRD) and scanning electron microscope and energy dispersive X-ray spectroscopy (SEM-EDS). The results showed that single-phased perovskite-type oxide powders with small particle size were obtained by the process, and the compositions of the productions agreed with the designed molar ratio. The electronic conductivity and ionic conductivity of La0.8Sr0.2Co1-yFeyO3-δ were investigated by DC four-terminal method and AC impedance spectroscopy, respectively. The electronic conductivity of La0.8Sr0.2Co1-yFeyO3-δ is approximately 2~4 orders of magnitude higher than the ionic conductivity. It was confirmed that the conductivities of the materials were strongly influenced by the composition anions, temperature and sample preparing process.